Detergent bars having lime soap dispersing characteristics



United States Patent 3,355,389 DETERGENT BARS HAVING LIME SOAP DISPERSING CHARACTERISTICS David M. Marquis, ()rinda, Califi, assignor to Chevron Research Company, a corporation of Delaware N0 Drawing. Filed duly 2t 1964, Ser. No. 383,914 11 Claims. (Cl. 252--121) ABSTRACT OF THE DISCLOSURE Detergent bar composition having improved lime soap dispersing property and suitable for use in hard water contained by incorporating a water soluble soap which may contain in addition a Water soluble non-soap synthetic detergent in a water soluble salt of thiodisuccinic acid having at least two hydrogen atoms of the carboxyl group replaced by an alkali metal or magnesium as a lime soap dispersant. The amount of the lime soap dispersant being incorporated may be between 5% and 25% by weight based on the total detergent bar composition.

This invention relates to detergent bars containing soap which do not react with the curd-forming components of hard water to form insoluble soaps. The bars may, in addition, contain a nonsoap synthetic detergent.

It is well known that the use of ordinary toilet soaps in hard water gives rise to the formation and precipitation of insoluble fatty acid salts, commonly referred to as lime soaps. These precipitated lime soaps tend to coagulate and form a sticky curd, which is especially noticeable in washstands, bathtubs, and the like, where it rises to the surface of the water and adheres around the tube or wash basin as a ring. In laundry applications the scum or curd affects the laundry tub in like manner but, in addition, adheres to the clothes. As a result, the clothes take on a gray, dingy appearance, develop spots upon ironing, and often a rancid odor. Similarly, when used for washing the hair, lime soaps are deposited thereon, giving the hair a coarse feeling and a dull appearance.

It has now been found that lime soap formation and precipitation can be substantially avoided by incorporating in the soap, e.g., a tallow soap, a minor but effective amount of a water-soluble salt of thiodisuccinic acid (Ho0CCH2CH-s-CH-OILCOOH) coon COOH in which at least two hydrogen atoms of the carboxyl groups have been replaced by a metal selected from the group consisting of the alkali metals and magnesium.

More specific examples of lime soap dispersants are dimagnesium thiodisuccinate, disodium and dipotassium thiodisuccinates, trisodium and tripotassium thiodisuccinates, and tetrasodium and tetrapotassium thiodisuccinates.

It has further been found that a thiodisuccinic acid salt of the type contemplated is efl ective to inhibit or prevent curd formation without substantially impairing the foam properties of the soap. 'Ihe lime soap dispersing agent of the present invention is effective in amounts ranging from about 5 to 25 percent by weight, based on soap and lime soap dispersing agent.

The soap which can be used in accordance with the 6 present invention is not critical. Any of the water-soluble 3,355,389 Patented Nov. 28, 1967 curd-producing soaps in bar form normally used in industrial laundering, and toilet applications are contemplated. As is known, these soaps can be prepared from a variety of fatty and oily materials, such as tallow, coconut oil, cottonseed oil, corn oil, soybean oil, olive oil, palm oil, lard, greases, fish oils, and the like. The cation portion of the soap is so selected as to impart sufficient hardness to the soap to form a bar. Thus, the cation can be sodium, potassium, or nitrogen-containing, such as the ammonium soaps or those derived from triethanolamine. In general, water-soluble sodium salts of fatty acids derived from tallow and coconut oil are preferred because of the ease with which they can be formed into a bar.

As indicated earlier, the invention also encompasses ternary mixtures of soap, of the type hereinabove described, a thiodisuccinic a-cid salt of the type specified, and a nonsoap synthetic detergent.

It has been proposed in the past to use nonsoap synthetic detergents, such as the organic alkyl sulfonates, alkyl sulfates, and alkyl benzene sulfonates, admixed with soap, to decrease its curd-forming tendency when used in hard Water. Even here, however, the problem of lime soap formation and precipitation is not satisfactorily overcome.

The synthetic detergent component, like the soap, is also not critical. Broadly, it falls within the class of surface-active materials which are the water-soluble salts, such as the sodium or magnesium salts, of organic sulfonic acids and of aliphatic sulfuric acid esters. In other words, synthetic detergents are contemplated which are watersoluble salts of organic sulfuric reaction products having in the molecular structure either a sulfonic acid or sulfuric acid ester radical.

As more specific examples of satisfactory synthetic detergents, there can be mentioned the Water soluble salts, such as the sodium or magnesium salts, of alkyl benzene sulfonates, in which the alkyl groups are of branched chain structure or of linear, or straight chain, structure, having an average of 8, preferably 10, to 15 carbon atoms in the alkyl radical; the water-soluble salts of alkyl sulfuric acid, having 8 to 18 carbon atoms in the alkyl group; the water-soluble salts, such as the alkali metal salts of sulfuric acid esters of primary normal aliphatic alcohols containing 10 to 18 carbon atoms, such as lauryl and oleyl alcohol; primary and secondary alkyl sulfates having pronounced detergent power and obtained from primary or secondary alcohols and olefins. Other examples of the synthetic detergent component include the sulfuric acid esters which are the water-soluble salts of sulfuric acid esters of polyhydric alcohols incompletely esterified with high molecular weight soap-forming carboxylic acids, such as the water-soluble salts of sulfuric acid esters of polyhydric alcohols incompletely esterified with high molecular weight soap-forming carboxylic acids, such as the water-soluble salts of sulfuric acid esters of higher molecular weight fatty acid monoglycerides, more specific examples being sodium glyceryl monolaurate sulfate and potassium 'glyceryl monopalmitate sulfate.

The method of addition of the additive of the present invention is not critical. It thus can be added to the crutcher after the soap has been made by saponification of fats. Or the additive can be added to soap chips and detergent in the amalgamator, if desired, along with other soap additives conventionally used, such as coloring agents, perfume, fillers, and the like,

The .ternary mixtures of .the .invention will generally comprise, in weight percent, based on soap, synthetic detergent, and lime soap dispersant, to 90, preferably 60 to 80, soap; 5 to 90, preferably to 30, nonsoap synthetic detergent; and 5 to 25, lime soap dispersant.

In evaluating a satisfactory lime soap dispersant, a good method and the one used in the examples hereinbelow appearing is as follows: A stock solution of the test dispersant is prepared by dissolving 1 part by weight of the dispersant in 99-parts of distilled-water. Stock solutions of tallow soapand of the various synthetic detergents are also prepared, again the concentration of the organic material in the solution being 1% by weight.

Since the stock solutions are made up to the same concentration, the relative amount of each solution deter- Combination soap-nousoap deter-gent bars containing the thiodisuccinic acid salt of the present invention were evaluated by handwashing in hard water. The tests tabulated in Table H were carried out -by a panel of three persons. Judgments were made as to how much lather and how quickly it formed compared with commercially available good quality toilet soap. Also subjectively determined was the quantity of lime soap curd remaining after washing of the hands in 1 liter of 200 and 300 p.p.rn. hard water as compared with an unmodified bar. The various bars were rated as being excellent, good, fair, and poor as indicated.

In making the bars of 'Table II, tallow and coconut soaps were grated into chips which were drymixed with TABLE-IL-COMBARS CONTAINING THIODISUCCINIC ACID SALTS Cone. Cone. Cone. Lather Lather Lime Soap Ex. Soap (Wt. Detergent (Wt. Dispersant (Wt. Quick- 4 Quan- Dispersa- -N0- Per- Per- ,Perness tity bllity cent) cent) cent) 11 Tallow/Coconut... 43/29 Sodium Alkyl Benzene'SulfonateL 14 Teatirasodiurtn Thio- 14 Good Good Excellent.

, succina e. None None Poor Poor. Sodium Alkyl Benzene Sulfonate o Good-.. Farr. Sodium AlkylBenzene Sulfonate 15 Dimagnesium Th o- 15 d0 do Excellent. disuccinate.

Sodium Alkylbenzene Sulionate 1 10 Magnesium Alkyl Benzene 1O Tetrasodium Thio- 1O do Fa1r Do.

SulfonateJ V disuccinate. 7 Sodium Alkyl BenzeneSulionateiL 15 do V 15 do Good D0.

1 Alkyl group is polypropylene of an average molecular weight of 265. 2 Contains 7% of lauric-myristic diethanolamide as a foam booster.

a Alkyl group is a mixture of straight chain alkyl groups containingdO through 13 carbon atoms.

mines the relative percents of tallow soap or tallow soap plus synthetic detergents and dispersant for each'test.;For example, a 10% dispersant test iscarried out as follows: Place '1 ml. of the dispersant solution and 9 ml. of-the tallow soap containing solution in the bottom of a IOO ml. stopper-ed graduate cylinder and swirl'it gently. When well mixed, dilute with 90 ml. of 334 ppm. hard water (2 parts calcium to l partmagne'sium, calculated as carbonates) atll0 -F. The final hardness is 300 ppm. The graduate is then shaken vigorously-for 15 seconds, and thenallowed to stand for 5 minutesrAt the end of-this time, the milliliters of curdare measured and recorded.

The following tabulated examples illustrate the practice of theinvention.

TAB LE I..-.LIME SOAP DISPERSANTS Compound Conc. Soap the, other ingredients. Aftenthorough mixing,.the composi characteristics and suitable for use in hard water, con- Tallow Soap do 'Tetpiisodiumthiodisuccinate 0 4 d0 -5 Disodiuinthiodisuccinate 6 Igepon T (Sodium N -Methyl-N- oleic acid taurate). 7 Dimag-nesiumthiodisuccinate 8 Commercial Sodium Polypropylenebenzene Sulfonate'D etergent. 9- Tetrasodiumthiodisuccinate s 5 Coconut Soap--- 10 Igepon '1 (Sodium N -l\lethyl- 7 Tallow Soap.

oleic acid taurate).

.H CO CO WOOHOO 7 Referring to Table I, it is noted that considerable curd formation occurs with untreated soap (Experiment -1). A combat-composed of commercial sodium polypropylene benzene sulfonate detergent and soap without lime soap 6F 0 dispersant isalso unsatisfactory (Experiment 8). The lime soap dispersant of the present invention (Experiments 2, 3, 4, 5, 7 and 9) are just as efiective, if not more so, than commercially available lime soap dispersant Igepon T (Experiments 6 and 10).

Sodium tallow soap had 5.5% water, and on acidification and extraction with petroleum ether gave 85.6% fatty acids. The fatty acid portion had an acid number-of 202 and an iodine number of 50, and contained 2% lnuric acid, 4% myristic acid, 33% palmitic acid, 22% stearic acid, and 39% oleic acid.

sisting essentially-of water-soluble soap .n'ormally .having poor-lime soap dispersi'ng :characteristicsand, as alime soap dispersant, a water-solublesalt-of thiodisuccinic acid,

having'at least two hydrogen :atomsro'f thecarboxyl groups 7 replaced by a metal selected from the group consisting of the alkali metals and magnesium, saidlime'soapdispersant being present .in an amountof about 5 :to 25 percent by weight, based on lime soap dispersant and soap.

2. A detergent bar according to claim :1, wherein the lime soap dispersant is tetrasodiuin thiodisuccinate.

3. A deter-gent bar according to claim -1, wherein'the lime soap dispersant is tetrapotassium thiodisuccinate.

14. A detergent bar according to claim 1, wherein the lime soap dispersant isdisodium thiodisuccinate.

5. A detergent bar according to claim 1, wherein the lime soap dispersant is dimagnesium thiodisuccinate.

6. A detergent bar having good lime soap dispersing characteristics, and suitable for use in hard water, consisting essentially of a water-soluble soap, a Water-soluble nonsoap synthetic detergent salt of an organic sulfuric reaction product having in its molecular structure a member selected from the group consisting of sulfoni acid and sulfuric acid ester radicals, and, as a lime soap dispersant, a water-soluble salt of thiodisuccinic acid having at least two hydrogen atoms of the carboxyl groups replaced by a metal selected from the group consisting of the alkali metals and magnesium, the aforesaid ingredients being present in proportionate amounts by weight percent based on soap, lime soap dispersant, and synthetic detergent ranging from 5 to 90, soap; 5 to 90, nonsoap synthetic detergent; and 5 to 25, lime soap dispersant.

7. Detergent bar according to claim 6, wherein the synthetic detergent is alkyl benzene sodium sulfonate having to carbon atoms in the alkyl groups.

8. A detergent bar according to claim 7, wherein the ingredients are present in proportionate amounts of to percent soap, 10 to 30 percent synthetic detergent, and 5 to 25 percent lime soap dispersant.

9. A detergent bar according to claim 8, wherein the lime soap dispersant is tetrasodium thiodisuccinate.

10. A detergent bar according to claim 8, wherein the lime soap dispersant is dimagnesium thiodisuccinate.

11. A detergent bar according to claim 8, wherein the lime soap dispersant is disodium thiodisuccinate.

References Cited UNITED STATES PATENTS 3/1956 Mulvaney 260-537 2/1966 Lew 252121 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,355,389 November 28, 1967 David M. Marquis t error appears in the above numbered pat- It is hereby certified the hat the said Letters Patent should read as ent requiring correction and t corrected below.

Coifimngl, .line 34,- for "tube" read. tub columns 3 and 4, TABLE .I, secondcolumn; line 4 thereof, for "do read Tetrapotassiumthiodisuccinate Signed and 'sealed this 31st December 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

6. A DETERGENT BAR HAVING GOOD LIME SOAP DISPERSING CHARACTERISTICS, AND SUITABLE FOR USE IN HARD WATER, CONSISTING ESSENTIALLY OF A WATER-SOLUBLE NONSOAP SYNTHETIC DETERGENT SALT OF AN ORGANIC SULFURIC REACTION PRODUCT HAVING IN ITS MOLECULAR STRUCTURE A MEMBER SELECTED FROM THE GROUP CONSISTING OF SULFONIC ACID AND SULFURIC ACID ESTER RADICALS, AND , AS A LIME SOAP DISPERSANT, A WATER-SOLUBLE SALT OF THIODISUCCINIC ACID HAVING AT LEAST TWO HYDROGEN ATOMS OF THE CARBOXYL GROUPS REPLACED BY A METAL SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METALS AND MAGNESIUM, THE AFORESAID INGREDIENTS BEING PRESENT IN PROPORTINATE AMOUNTS BY WEIGHT PERCENT BASED ON SOAP, LIME SOAP DISPERSANT, AND SYMTHETIC DETERGENT RANGING FROM 5 TO 90, SOAP; 5 TO 90, NONSOAP SYNTHETIC DETERGENT; AND 5 TO 25, LIME SOAP DISPERSANT. 